import numpy as np
import pandas as pd
import os

a_array = np.array([
    [1, 2],
    [3, 4]
])

a_df = pd.DataFrame(
    {"a": [1, 3],
     "b": [2, 4]}
)

print(f'numpy array:\n {a_array}')
print(f'\npandas df:\n {a_df}')